Kyocera CNMG120404PG CA125P TMK00008 Turning Insert - General Purpose

Product Overview

The CNMG120404PG CA125P TMK00008 is a premium diamond insert manufactured by Kyocera in Japan. Engineered for general purpose applications, this negative-style insert offers two usable cutting edges per side, delivering exceptional cost-per-edge economy. The sharp point for profiling and finishing. With 12mm inscribed circle diameter, 4.76mm thickness, and 0.4mm nose radius, this insert provides optimal cutting geometry for general purpose operations on CNC turning centers. The PG (Positive General) geometry combined with CA125P PVD coating ensures reliable chip control, extended tool life, and consistent surface finish across a broad spectrum of steel workpiece materials.

ISO Designation Breakdown

The CNMG120404PG follows the ISO 1832 standard indexable insert designation system:

• C — 80° rhombic shape (diamond, two cutting edges)
• N — 0° clearance angle (negative insert, double-sided)
• M — Tolerance class ±0.13mm (inscribed circle & thickness)
• G — Cylindrical hole with countersink (double-sided clamping)
• 12 — 12mm inscribed circle diameter (IC)
• 04 — 4.76mm nominal thickness
• 04 — 0.4mm nose radius
• PG — PG (Positive General) chipbreaker geometry

Engineering Dimensions & Geometry

Grade Details — Key Grade Characteristics

CA125P is a PVD-coated carbide grade specifically developed for steel machining (ISO P25 application group). PVD-coated carbide for general steel machining with balanced toughness and wear resistance. The multi-layer PVD coating provides outstanding wear resistance, thermal stability, and extended tool life in both continuous and interrupted cutting conditions.

• Substrate: Fine-grained tungsten carbide (WC-Co) with optimized cobalt binder content
• Coating: Multi-layer PVD, 2–4 μm total thickness
• Hardness: 1,550 HV (Vickers hardness)
• Transverse Rupture Strength: 3,000 MPa
• Application Group: ISO P25 (steel machining)
• Max Operating Temperature: 850°C
• Best For: General steel turning & semi-roughing

Grade Comparison Matrix

Chipbreaker Profile

The CNMG120404PG features the PG (Positive General) chipbreaker, a versatile geometry designed for general-purpose turning across a wide range of cutting parameters. The balanced groove width and land design provide reliable chip control for both finishing and medium-duty operations in standard steel machining.

• General-purpose groove for versatile application range
• Balanced chip control across varied feeds and depths
• Optimized for depths of cut (0.3–2.5mm)
• Reliable performance in carbon and low-alloy steels
• Good compromise between surface finish and material removal rate
• Suitable for job shops and mixed production environments

Recommended Applications & Workpiece Materials

The CNMG120404PG CA125P is optimized for the following materials and application scenarios:

• Carbon Steels: C35, C45, C50, 1045, 1050 — Excellent performance
• Alloy Steels: 4140, 4340, 16MnCr5, 20MnCr5 — Consistent tool life
• Tool Steels: H13, D2, O1 — Pre-hardened material machining
• Bearing Steels: 100Cr6, 52100 — Precision surface requirements
• Cast Steels: GS-25, GS-45 — General cast steel components

Note: For austenitic stainless steels (304, 316), consider grade CA6535 or PR1225 for optimal performance.

Application Map by Operation

Recommended Cutting Conditions

Values are starting recommendations. Adjust based on machine rigidity, coolant application, and workpiece condition. Use lower end for interrupted cuts or less rigid setups.

Operating Guidelines

• Coolant: Flood coolant recommended at 6–8% concentration for optimal chip evacuation and thermal management. Minimum flow rate 5 L/min directed at the cutting edge. For hard turning (PQ chipbreaker), consider minimum quantity lubrication (MQL) or dry cutting to avoid thermal shock.
• Tool Overhang: Keep tool overhang to minimum possible (≤4× shank diameter for boring bars). Excessive overhang promotes vibration and chatter marks, especially with larger 12mm inserts.
• Insert Seating: Clean toolholder pocket and insert seat thoroughly before mounting. Negative inserts require precise seating for both top and bottom surfaces. Use torque wrench for screw clamping (recommended 2.5–3.5 N·m).
• Edge Preparation: Do not touch the cutting edge with bare fingers. Oils and moisture can promote micro-chipping at high temperatures. Handle inserts with clean gloves or edge protectors.
• Wear Monitoring: Monitor for flank wear (VBmax = 0.3mm) and crater wear (KT = 0.15mm). Replace insert before catastrophic failure to protect workpiece surface. With 2 edges per side, index promptly when wear limits are reached.
• Speed Ramping: When starting a new batch, begin at 70% of recommended Vc and increase incrementally to find the stable operating window for your specific machine and setup. For PG chipbreaker, optimal performance is typically achieved at 80–90% of max Vc.
• Index Strategy: As a double-sided negative insert, this tool offers 2×2 = 4 total cutting edges. Index systematically to maximize economy and maintain consistent tool life tracking.

Toolholder Compatibility

The CNMG120404PG is compatible with standard MCLNR/L and PCLNR/L toolholders designed for 80° diamond negative inserts with 12mm IC. The sharp 80° point angle enables precise profiling, facing, and contouring operations with excellent accessibility to tight corners and shoulders.

• Toolholder series: MCLNR, MCLNL, PCLNR, PCLNL
• Clamping: Lever type or top-clamp (double-sided)
• Insert seat angle: 0° negative
• Compatible shank sizes: 16×16mm, 20×20mm, 25×25mm, 32×32mm
• Max overhang for boring: 4× tool diameter

Packaging & Ordering Information

• Packaging: Each insert is individually sealed in anti-corrosion VCI (Volatile Corrosion Inhibitor) film and packed in Kyocera-branded plastic boxes of 10 inserts.
• Minimum Order: 10 inserts (1 box). Bulk pricing available for quantities of 50, 100, and 500 inserts.
• MPN: TMK00008 — Use this manufacturer part number for precise ordering and inventory tracking.
• Batch Number: 26-5342 — Traceability code for quality control and warranty claims.
• Warranty: 12-month manufacturer warranty against material and coating defects under normal operating conditions.
• Storage: Store in original packaging at 15–25°C, humidity <60% RH. Avoid direct sunlight and contact with corrosive chemicals.

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